1. Field of the Invention
The present invention relates to a digital image processing technique, and more particularly to a method and apparatus for processing breast images and using a shape model for feature removal/positioning in breast images.
2. Description of the Related Art
Mammography images are powerful tools used in diagnosis of medical problems of breasts. An important feature in mammography images is the breast shape. Clearly detected breast shapes can be used to identify breast abnormalities, such as skin retraction and skin thickening, which are characteristics of malignancy. Clear breast shapes also facilitate automatic or manual comparative analysis between mammography images. Accurate breast shapes may convey significant information relating to breast deformation, size, and shape evolution. The position of the nipple with respect to the breast can be used to detect breast abnormalities. Knowledge of the mammogram view is also important for analysis of breast images, since the mammogram view sets the direction and geometry of a breast in a mammogram image.
Unclear or inaccurate breast shapes may obscure abnormal breast growth and deformation. Mammography images with unclear, unusual, or abnormal breast shapes or breast borders pose challenges when used in software applications that process and compare breast images.
Due to the way the mammogram acquisition process works, the region where the breast tapers off has decreased breast contour contrast, which makes breast borders unclear and poses challenges for breast segmentation. Non-uniform background regions, tags, labels, or scratches present in mammography images may obscure the breast shape and create problems for processing of breast images. Reliable breast shape detection is further complicated by variations in anatomical shapes of breasts and medical imaging conditions. Such variations include: 1) anatomical shape variations between breasts of various people or between breasts of the same person; 2) lighting variations in breast images taken at different times; 3) pose and view changes in mammograms; 4) change in anatomical structure of breasts due to the aging of people; etc. Such breast imaging variations pose challenges for both manual identification and computer-aided analysis of breast shapes.
Disclosed embodiments of this application address these and other issues by using methods and apparatuses for feature removal and positioning in breast images based on a shape modeling technique for breasts. The methods and apparatuses also use an atlas for location of features in breasts. The methods and apparatuses automatically determine views of mammograms using a shape modeling technique for breasts. The methods and apparatuses perform automatic breast segmentation, and automatically determine nipple position in breasts. The methods and apparatuses can be used for automatic detection of other features besides nipples in breasts. The methods and apparatuses can be used for feature removal, feature detection, feature positioning, and segmentation for other anatomical parts besides breasts, by using shape modeling techniques for the anatomical parts and atlases for locations of features in the anatomical parts.